There are numerous multi-story cold storage warehouses in this country having interiorly disposed elevator shafts which are partially or completely surrounded by the cold storage area the temperature of which is usually maintained between 0.degree. and -20.degree. F. A constantly recurring problem in buildings of this type is the build up of frost and ice on all surfaces inside the elevator shaft. This is caused over a period of time by the condensation of moisture in the shaft on the exposed surfaces and subsequent freezing due to gradual transfer of heat from the shaft interior to the remainder of the cold storage area. Everytime that the elevator doors are opened, additional air enters the shaft and in addition there is a pumping effect due to movement of the elevator car within the shaft. At the present time, many such installations are permitted to continue to operate in this manner until the ice build up in the shaft is so excessive that it interferes with the operation of the elevator. The remedy in the past had been to employ workmen to ride in or on the elevator car and physically chip the ice from the surfaces where it has accumulated. This is not only an expensive procedure but also a dangerous one for the workmen concerned. Further, the existence of ice in this location can be detrimental to insulation and to the structure of the warehouse itself.